A Simplified Method for Mitochondrial DNA Extraction from Head Hair Shafts
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ABSTRACT: DNA isolation from hair shafts can involve a number of steps, each of which adds time to the procedure and increases the risk of contamination. A simple alkaline digestion procedure that directly dissolves hairs was developed and compared with a widely used glass grinding/organic extraction method, using samples collected from 30 volunteers with varying population ancestries, hair colors, and hair treatments. A 203 bp mtDNA product could be amplified from 90% of samples extracted by alkaline digestion and 73% of hairs extracted by glass grinding. DNA obtained from alkaline digested hair generated equal or greater amplification success for virtually all criteria examined, and mtDNA sequences matched buccal control sequences in all cases. The two methods were similar in DNA yield (amplification success at template dilution) and quality of DNA obtained (amplicon length). Alkaline digestion of hair shafts required 6–7 h to complete, compared to 22–24 h for glass grinding, and proved a less laborious yet equally robust method for mtDNA extraction. KEYWORDS: forensic science, DNA typing, mitochondrial DNA, alkaline digestion, sodium hydroxide, glass grinding